Stereotactic devices are used for accurate surgical positioning of probes, electrodes, catheters, and other intra-body devices, such as in the brain, spine, lung, and liver. Stereotactic surgical procedures to place these types of devices within body or tissue can require accuracy to within millimeters or even micrometers. Such accuracy can depend upon the stereotactic devices used to guide the intra-body devices to specific points in the body.
Placement of intracranial devices requires particular accuracy. There are several types of stereotactic devices used for guiding and placing intracranial devices. Some of these devices fix the position of the head and utilize a Cartesian coordinate system to relate the known features on skull to an external grid. Others use a frame system that attaches to the skull and utilize a polar coordinate system to relate features on the skull to the known locations of other features. One specific system requires a burr-hole be drilled into the skull and the stereotactic device is affixed within the burr-hole. The stereotactic device is then used to guide intracranial devices into the brain through the burr-hole.
Stereotactic devices utilized for implantation of devices in humans can be quite different than those used for implantation into animals. Even stereotactic devices used for animal implantations can be different for different animal species. The differences in anatomy, size, orientation of features, and points of attachment necessitate different types of stereotactic devices for different species.
Another issue is intracranial devices that are permanently or semi-permanently emplaced for long term treatment, therapies, or research. Such intracranial devices often have externally exposed ends, protruding outside the body. The exposed ends should be supported to ensure that the intracranial placed devices remain in position. Those that provide a direct conduit into the body need to be covered to ensure that undesirable materials are not introduced into the brain. Intracranial devices implanted in animals can be particularly problematic, since the animal will often actively attempt to remove or displace the exposed ends.